Switch



Patented Nov. 3, 1942 UNITED STATES}; PATE T F FICE Q swrrcn Arnold Deutschmann, Center Newton,

sp ncauonmmn 1, 1940, Serial at. 321,685

' lu-Claiins. (Cl. zoc-s'i) The present invention relates to electric switches and in particular to the type of switch which operates with a small motion and with desired regulated pressure. Such devices of electric switches are commonly in use'and usually comprise a flexible leaf spring in which a strain is placed upon the spring in such a way that a slight motion of the spring by pressure at one point willcause the spring to snap'and assume another position. A common type of spring leaf. used for this purpose is a fiat leaf spring of phos-' phor bronze 'or other spring material which has a slot along the. middle and bowed slightly inward on either side to give the spring a definite. inclination from an unstrained level plane. The leaf spring is usually fixed at its unstrained end and positioned with-the inclination from a level plane downward.

will cause the other end of the spring to snap upwards with a sudden snap action.

condition and then after the spring has been mounted; to apply-the strain gradually until the desired pressure and movement has been attained.

This is accomplished in the present invention by adjusting the strain on the leaf spring from substantially zero force to the desired final force. In this way the switch may be accurately adjusted and readjustedif necessary after the first adjustment has been made. The switch "cover 3 rests. =The base and cover are preferably made of insulating material such as hard rubber, Bakelite or other suitable material. The I g In Figure 1, I indicates a base supportwhich Figure 3 shows a detailof the leaf spring. 1 Figure 4. shows a modification 'of the leaf spring shown in Fig.3.

Figure "5: shows a detail the leaf spring of Figure 4].

Figure 6 shows a modification of a detail on the line 6-6 of Figure-'7, and, Figure 7 shows a plan view of the detail, and, Figure 8 shows a section of the detail on the line 8-8 of Fig. 6.

'.is -provided with a shoulder 2 upon which the base i is provided with' a slot 4 upon which is positioned 'plates 5 and 6. These plates may be A slight pressure on the top of the leaf spring in its center near its fixed end of conducting material if desired and are of such dimensions that they ride freely in the slot or groove section 4. As indicated in Figs. 1 and-2 one of these plates or blocks 6 is fixed to the base- I by means of 'the screw 1 which may be terminatedin a nut 8 and supporttheterminal lug 8. 'I'he'plate 6 is also provided with a per- Q foratiomextending through the'plate it from may even be adjusted after it has .been installed i in the unit in which itis operated. The adjustment may thenbe made in accordance with the.

desired'or necessary condition of operation.

The invention will be more fully explained and understood from the description given below when taken in connection with the showing an embodiment of the invention, in which: Figure l shows a'sectionthrough-the switch with some elements left in full.

-. Figure 2 shows'atopsection taken on'the line 2 201 8 01, 1

one side to'the other side in which is positioned a stud ll threaded at its end [2 where it enters the side ofthe block 5. The block} is similarly threaded and is free from the base I. When '30 therefore the stud II is" turned at its screw head 13, the plate 5- is drawn towards the plate ii.

Each block 5 and 6 holds one side of the leaf spring I4. This is preferably accomplished by other ends 22 and 23 of the spring may be im- 0 tlally b'owed together and held in place by means of the band 24 which fastens around the endofthe spring as indicated in Figure 2 and which may be riveted tothe spring legs. Any other method of bowing in the free end of the spring bowing in of the end 26 relieves the strain which might be-put on theother' end of the spring.

However this initial bowingein asindicated by I n addition. to am it localizes the the dotted linesof .3', maksit possible to regulatethe tension'for the-operation of the.

spring at the other-end with very little adjustment or bowingin of the fixed end of the spring.

of the support for means of'the machine screws l5 and I6 screwing into the block 5 and 5 respectively, through the holes ll' and i8. Therefore as the stud II is turned. atension is placed between the legs '40- and 2| at the supported end of the spring. The

any of course be used; Since both ends of the spring are slotted as indicated at 25 and 26, the

point of applie v at its fixed ends.

' area beneath the pin 21.

cation of the pressure so that the spring may be very efllciently operated.

In the assembly or the unit as shown in Figures 1, 2 and 3, the wrapper 24 is first placed around i the free end of the spring M. The spring is then put in position by being fastened to the plates and 6 by means of th screws l6 and [5 in such a way that no tension will be imposed upon the spring. A pressure device may then be applied to the pin 21 as the head [3 of the stud ii is carefully turned until the spring will snap from its bowed down position with th end 24 in contact with the contact plate 28 to its upward position in contact with the contact plate 29. The base I may be shaped with a supporting extension 30 to limit the throw of the spring I4. This motion may be regulated to the order of M of an inch with slight pressures of the order of ounces or-fractions of an ounce. After the desired pressure is obtained by adjustment of the stud II this may be locked in position if desired so that no further adjustment should be made.

In Figure -1 is should be noted that the contact plate 28 may be adjusted vertically in the threaded bushing 35 by turning the screw 32 up or down,

so that in the lower contact position of the wrapper 24 the desired pressure against the plate 28 may be obtained after the adjustment of the moveable plate or block 5 has been made which controls the action of the end of the spring. The

leaf spring [4 so that in this case the snapping action of the spring downward would be accomplished by pressure on the underneath side of the spring. a In the modification of Figures 6, 7 and 8, the blocks or plates 60 and 6! corresponding to the plates 50 and 5| of Figure 5 are grooved or slotted on their end as indicated at 62 and 63 (Figure 6) to receive the projecting flanges 64 and 65 of the support member 66 which is anchored in the base 61 by the pins 68, 68, or in any other suitable way. The support 66 has upwardly extending sides 69 and 10 from which the flanges 64 and 65 project.

Initially the adjusting screw 1| is put. in place in the plates 60 and 6| with the plates spaced apart so that the rivet holes 12 and 13 in the plates align with those in the spring in their untensioned position. The plates are then slid on the flanges as tracks until they are centered on the base 61. The plates may then be locked in, on one side, by the downward inclinationof the flanges and 65 as indicated at 14 (Figure point at which the pin 21 should operate. If a more gradual adjustment is desired, the slot 25 is usuallymade shorter than the slot 26.

In Figures 4 and 5 is shown a modification of the invention indicated in the other figures.

In Figure 4 theleafspring 40 is provided with one slot 4| at its free end and two slot 42, 43 The center forked member 44 in this case is attached to the plate 46 by means of the screw 41 and the plate 46 is fixed to the base by means of the screw 45. The end forked elements 48 and 49 arescrewed to the blocks 66 and 5| by means of the screws 52 and 53. The blocks 60, 46 and 5| hav an aligned hole with the hole in the block 5| threaded to receive the screw 64. As the head of the screw .54 is turned, the blocks 50 and 5| ar drawn together thusexerting a tension which is located just beyond the slots 42 and 43 in line approximately with the center section 44 of the leaf spring. A lock washer 66 may be provided so thatthe screw 64 will be held in position after it is adjusted.

In the operation of the switch mechanism after the leaf spring has been mounted in place the screw 64 will be tightened producing a sensitive This action will produce a strain in the spring under the pin 21 and bend the spring slightly downward to the contact plate 28. If the freeend of the spring has been tensioned, this will also produce a sensitive area underneath the pin 21 and these two BEE-{from on another, a sensitive area would stillbpioduced-under the point 21 which would 8) and on the other side by the punching of the flange down as indicated at 15, which of course is done after the Plates are put in position. When the plates are put in position, the spring assembly with the spring, the plates and adjusting screw have already been put together. After this assembly is put in place, the adjusting screw can be adjusted for the desired pressure and throw.

The advantageof thi modification is rapid assembly. Having now described my invention, I claim: 1. An electric switch comprising a leaf spring having a free end and a fixed end, said sprin being bifurcated at both ends, means mounting said fixed end of the spring, comprising independent mounting elements for each bifurcated end, and means for adjusting the position of said mounting means to strain said leaf spring whereby a set is provided for said leaf spring inclining the free end of the spring away from its normal level position and meansfor exerting a pressure on the convex side of the spring at a point of balance whereby a slight movement at the point of pressure will cause the free end of the spring to snap in the other direction.

plurality of block elements positioned in saidguideway, means for adjustably positioning said block elements in spaced relation in said guideway, a leaf's'pring having bifurcated members at each end, means mounting said bifurcated elements at one end, one on each block, a contact cause an inclination upwards ofthe end of the element mounted at th other end of said leaf spring and exerting a towing-in effect of the 'bifurcated ends of said last elements whereby said leaf spring is bowed normally in the direction away from the original level of said spring and means for applying pressure on the side of said spring from which the free end of the spring is bowed.

3. An electric switch comprising a base insulating element, a leaf spring having one end slotted, means fixing the slotted end of the spring including means-for drawing together the means fixing said slotted end of said spring whereby the leaf spring at its other end is drawn away from its normal plane position and a sensitive area created in the vicinity of the spring at the end of the slot, contact means arranged opposite the free end of the spring, and means for exerting a pressure on said spring in said sensitive area for causing the spring to snap in a direction at its free end.

4. An electric switch com rising a base insulating element, a leaf spring having slotted ends, means fixedly towing in said leaf spring at one end and means adjustably towing in said spring at the other end including means mounting each slotted portion of said spring at one of said spring ends, said towing in means creating a sensitive area in said spring whereby pressure on one surto its; normal plane face will cause the spring to snap at its free end in the opposite direction and means for exerting pressure on said spring in said sensitive area.

5. An electric switch comprising a base insulatingelement, a leaf spring having slotted ends, means for towing in one of said slotted ends, means for mounting the other of said slotted ends, means for adjustably towing-in the mounted slotted ends of said spring whereby a sensitive area is created in the vicinity of the spring between said slotted ends, contact means arranged opposite the free end of the spring and means for exerting a pressure on said spring in said sensitive area for causing the spring to snap in a direction to its normal plane at its free end.

- 6. An electric switch comprising a base insulate ing element, a leaf spring, having'slotted ends, contact means mounted on one of said slotted ends and exerting a straining action on the legs adjacent the slot, means mounting the other slotted end of the spring including means for adjustably exerting a strain on the sections of the spring on either side of the slot whereby asensitive area is created in thevicinity of the sprin between the ends of the slots drawing the sprin away from its normal plane position, contact means arranged opposite the free ends of the spring and adapted to complete an electrical circuit with the contact means on said spring, and means for exerting a pressure on said spring in the said sensitive area for causing the spring to snap in a directionto its normal plane at its free ends.

7. An electric switch comprising a base insulating element, a leaf spring having one end slotted, means'for mounting the slotted end of said spring including a plurality of blocks, one for mounting each slotted section of said spring, means for adjustably drawing together said mounting blocks whereby the leaf spring at its other end is drawn away from its normal plane position and a sensitive area created in the vicinity of the slot end slotted, means for straining one end of said slotted spring in a permanent fixed position,

means for adjustably straining the other end of said slotted spring including means for mounting the slotted end of said spring comprising a plurality of block elements, one for mounting each 9. An electric switch comprising a base insulating element, a leaf spring having both ends slotted, means for fixedly towing in one end of the slotted spring, means for adjustably towing in the other end of said slotted spring comprising means mounting each slotted section ofthe spring, means permanently fixing one of said mounted sections to the insulated base and screw means passing through said mounted section and threading into another of said mounting means for adjustably positioning said mounting means of said spring, contact means arranged opposite;

the free end of the spring and means for exerting a pressure on said spring in said sensitive area for causing the spring to snap in a direction to. its normal plane at its free end.

8. An electric switch comprising a base insulating element, a leaf spring having bothl'ends' *relative to each other whereby the leaf spring at its other end is drawn away from its normal plane position and a sensitive area created in the vicinity of the spring between the ends of the slots, contact meansarrang'ed opposite the free end of the spring and means for exerting a pressure on said spring in said sensitive area for causing the spring to snap in a direction to its normal plane at its free end. J

10. An electric switch comprising a base in-' sulating element, a leaf spring having a plurality of slots at each end thereof, means for permanently straining the sections of said spring ad-- jacent said slots at one. end thereof, means for,

'adjustably straining the sections of said spring adjacent said slots at the other end thereof including block means for independently mounting each section of said spring formed by said slots, means permanently fixing one of said block sections to said insulating elements and screw means for adjustably moving the other of said blocks relative to the fixed block whereby the spring at its other. end is drawn away from its normal plane position-and a sensitive area created in the vicinity of thelspring at the end of the slot, contact j means arranged opposite the: free end of the spring and means for exerting a pressure in said spring insaid sensitive area for causing the spring to snap in a direction to its normal plane at its free end. v

. ARNOLDDEUTSCHMANN. 

